Introduction
The Lens Comparison Tool lets you compare two lens and sensor combinations side by side, showing you the effective field of view, equivalent focal length on full frame, and the resulting crop factor for each. You select a sensor size and focal length for each column, and the tool calculates and visualizes the difference in framing. This is essential when you are switching between camera systems (such as using a Super 35 camera for narrative work and a full-frame camera for documentary) or when renting lenses designed for one format and using them on another. The tool removes the guesswork from format-crossing decisions and shows you exactly what framing you will get before you commit to a lens package.
What This Tool Calculates
Modern productions frequently use multiple camera systems within the same project. A feature film might pair an ARRI Alexa 35 (Super 35 sensor) with a Sony Venice (full frame) for different shooting scenarios. Each camera's sensor size changes how the same lens performs. A 50mm lens on Super 35 frames like approximately a 75mm on full frame. If you do not account for this, you end up with mismatched coverage between cameras. Rental houses carry lenses designed for Super 35, full frame, large format, and Micro Four Thirds systems. Knowing exactly what a given focal length does on your specific sensor prevents expensive rental mistakes and on-set surprises when the framing is not what you expected.
The Formula and How It Works
Field of view is determined by the relationship between focal length and sensor dimensions. The horizontal field of view in degrees equals 2 times the arctangent of (sensor width / (2 times focal length)). Crop factor is calculated by dividing the full-frame diagonal (43.27mm) by the actual sensor diagonal. Equivalent focal length is the actual focal length multiplied by the crop factor. The tool performs these calculations using precise sensor dimensions for each format, giving you accurate results rather than the rounded approximations often quoted in marketing materials.
Real-World Examples
How to Use This Tool
Select a sensor format for the first comparison column (Full Frame, Super 35, APS-C, Micro Four Thirds, or others). Enter the focal length of the lens you plan to use with that sensor. Repeat for the second column. The tool displays both setups side by side with their field of view in degrees, equivalent full-frame focal length, and crop factor. Use this to find which lens on Camera B gives you the same framing as your lens on Camera A.
Tips from Working Professionals
| Detail | Value |
|---|---|
| Cinematographers recommend testing your specific lens and camera combination before the shoot day whenever possible, because crop factor calculations assume the lens perfectly covers the sensor, which is not always true with adapted lenses. | |
| Some Super 35 lenses vignette on full-frame sensors, and some older lenses designed for larger formats produce softer corners on smaller sensors due to the angle of incidence at the sensor edges. | |
| When matching cameras on a multi-camera production, start by choosing your key framing (usually the close-up) and work backward to determine which lenses give you matching fields of view on each body.. |
Pro Tips and Common Mistakes
Pro Tips
- Cinematographers working with multiple camera systems use this tool constantly.
- Camera assistants building lens packages for shoots that involve format switching need it for prep.
- Rental house staff use equivalent focal length calculations when helping clients select appropriate lenses for their cameras.
- Film students learning the relationship between sensor size and lens behavior develop stronger technical instincts by experimenting with this tool..
Common Mistakes
- Does crop factor affect depth of field? Indirectly, yes.
- A smaller sensor requires a wider lens to achieve the same framing, and wider lenses have deeper depth of field at the same aperture.
- So an APS-C sensor produces deeper depth of field than full frame when framing the same shot at the same aperture.
Frequently Asked Questions
Is crop factor the same as speed booster ratio?
No. A speed booster reduces the effective crop factor by a specified amount (typically 0.71x). Multiply your sensor's crop factor by the speed booster ratio to get the effective crop factor.
Do anamorphic lenses change the calculation?
Anamorphic lenses affect the horizontal field of view by their squeeze factor but not the vertical. Use the Anamorphic Desqueeze calculator for those calculations.
Start Calculating
Many lens comparison tools online use simplified crop factor approximations that ignore the actual sensor dimensions. This tool uses precise manufacturer sensor measurements for each format, giving you accurate field of view calculations rather than rough estimates. It is free, runs instantly in your browser, and is designed specifically for cinematographic lens selection rather than photography.
